Motor car bodies are conventionally manufactured using preformed pressed panels, the panels being joined together by welding or other means to form a sufficiently rigid and strong structure onto which a roof panel, doors, engine, suspension, and like components can be mounted. The pressed panels which make up the bodies are shaped to conform with the style or model of motor car to be manufactured and different models of car generally use differently shaped panels to form the body. Thus, for example, an estate car and a four door car of the same basic type and model will be formed of completely differently shaped side panels, even though the lower portions of the two cars are identical.
The press machines and associated dies therefor used for producing individual panels are very costly and accordingly, in order to recoup the capital costs of those machines and die tools, it is necessary for car manufacturers to produce large numbers of cars from the same press. This factor works against the introduction of lower volume models as the lower volumes simply do not recoup the outlayed capital costs.
In an attempt to decrease the costs of tooling, the industry has looked towards plastic or other low cost material dies. Plastic dies are indeed less expensive than corresponding metal dies and it is, in some circumstances, possible to use plastic die parts rather than the more expensive metal die parts. Plastic parts do not, however, last as long as metal parts and accordingly plastic tools are only suitable for shorter production runs. Clearly, if it is known that a particular model of car will only be made in low numbered runs then it is appropriate to use plastic die tooling. However, if it turns out that there is a need to extend the particular run then, where plastic tooling has been used, this is not always possible. Whatever material is adopted for die tooling, the cost of tooling is expensive and adds significantly to the cost of vehicles and detracts from manufacturers' discretion to change models in response to market demands.